Capital Rationing

Capital rationing is the process of selecting which investment projects to fund when there is not enough capital to pursue every available opportunity that clears your return threshold. Rather than taking every project with a positive net present value, the company must choose among competing uses for a limited pool of money. Capital rationing forces disciplined prioritization and is typically solved using the profitability index, which ranks each project by the value created per dollar invested.

Think of capital rationing like choosing which flights to book for a business trip with a fixed travel budget: you rank them by value delivered per dollar and fund the best ones until the money runs out.

Hard Rationing Comes from Outside; Soft Rationing Comes from Within

Hard capital rationing occurs when external constraints limit your access to capital. Your credit rating may have been downgraded, making bank loans unavailable at reasonable rates. Equity markets may be closed during a downturn. Existing loan agreements may contain capital expenditure covenants that cap new investment. These constraints are imposed on you by outside parties or market conditions.

Soft capital rationing is self-imposed. Management sets a capital budget below the theoretical maximum the company could deploy. Common reasons include risk management, a policy of funding investment only from operating cash flow, or a desire to maintain a strong balance sheet. Many disciplined companies limit annual capital expenditures to 70% or less of projected operating cash flow as a soft rationing discipline.

The Profitability Index Ranks Projects Under a Budget Constraint

The profitability index divides the present value of a project's future cash flows by its initial investment cost. A profitability index above 1.0 means the project creates value. When you face capital rationing, you rank all candidate projects by profitability index from highest to lowest and fund them in that order until the budget is exhausted.

This approach maximizes total value created per dollar spent rather than simply funding the single project with the highest absolute net present value. A large project with a high net present value but a low profitability index may generate less total return than multiple smaller, more capital-efficient projects that fit within the same budget constraint.

Multi-Period Rationing Requires Linear Programming

When capital constraints span multiple budget years, the profitability index ranking alone no longer produces the optimal solution. Projects that require phased investment across years interact with each other in ways that single-period analysis cannot capture. Linear programming solves multi-period capital rationing by optimizing simultaneously across all projects and all future periods.

Sources:
https://www.superfastcpa.com/what-is-capital-rationing/
https://corporatefinanceinstitute.com/resources/accounting/capital-rationing/
https://www.accountingtools.com/articles/capital-rationing.html
https://efinancemanagement.com/investment-decisions/types-of-capital-rationing-hard-and-soft
https://financialmodelslab.com/blogs/blog/capital-rationing